The present invention relates to semiconductor devices and manufacturing methods thereof, and more particularly, to a technique effectively applied to a semiconductor device with a nonvolatile memory and a manufacturing method thereof.
As an electrically writable and erasable nonvolatile semiconductor storage device, an electrically erasable and programmable read only memory (EEPROM) is widely used. Such a storage device (memory), typified by a flash memory currently used widely, includes a trap insulating film and a conductive floating gate electrode enclosed by an oxide film, under a gate electrode of a MISFET. The storage device is to store therein a charge storing state of the floating gate or trap insulating film as storage information, and to read the information therefrom as a threshold of the transistor. The trap insulating film is an insulating film that can store therein charges, and is a silicon nitride film or the like by way of example. The charging and discharging of charges into such a charge storing region shifts the threshold of the MISFET to operate the storage device as a memory element. The flush memory is a split gate cell using a metal-oxide-nitride-oxide-semiconductor (MONOS) film. Such a memory uses the silicon nitride film as the charge storing region to have the following advantages. Specifically, the memory has the excellent data hold reliability because of storing charges discretely as compared to the conductive floating gate film. Thus, the memory can thin oxide films located under and above the silicon nitride film because of the excellent data hold reliability to thereby decrease the voltages for the writing and erasing operations.
Japanese Unexamined Patent Publication No. 2010-183022 (Patent Document 1) discloses a technique regarding a semiconductor device including a memory region, a power feeding region, and a capacitor region.